• English / United States: Ilunas
• Japanese / Japan: カツキ
• Japanese (Romanized) / Japan: Katsuki
• Japanese (TL) / Japan: Katsuki

Ilunas is a descendant of Luno, the brother of Sorin who was the lord of the Eclipse Castle in the Johto Region. He initally kidnapped Chloe Cerise thinking she was Soleil and demanded that he be named the new lord of the Eclipse Castle. His plan failed when he didn't realize that Chloe Cerise and Soleil looked alike, so he outright attacked Soleil during the Eclipse Festival ceremony.

Ilunas's Japanese name has the moon (tsuki 月) part of his ancestors Tsukiya's name as part of his name. Because of Luno failed coup attempt, his ancestors lived in secret for a long time until Ilunas's attempt. Helia did not know of him until the day of the eclipse and she was sorry he had to endure so much hardship during his life.

After he tried to fight Soleil and lost the battle, Soleil still decided to allow him to become her friend and help her as the mistress of the Eclipse Castle, as she and Helia had been waiting for their missing 'moon' to finally return to support each other. He seemed to agree with her proposal.